1. Field of the Invention
The present invention relates to wipers that are used in vehicular mirrors which can be electrically tilted, such as a door mirror, a side-view mirror, etc.
2. Description of the Related Art
Conventionally, some of the vehicular door mirrors and side-view mirrors are provided with a wiper which wipe waterdrops attached to the surface to ensure visibility.
FIG. 14 shows a side-view mirror 1 provided with such a wiper function. The side-view mirror 1 is equipped with a mirror main body 10, a wiper main body 20, and a link mechanism section 30 connecting this wiper main body 20 with the mirror main body 10.
The mirror main body 10 is equipped with a synthetic resin housing 11, a reinforcement plate 12 fixed to the housing 11, and a mirror drive unit 13 fixed to the reinforcement plate 12. Furthermore, the mirror main body 10 is equipped with a wiper drive unit 14 fixed to the housing 11, rods 15 fixed to the mirror drive unit 13, a mirror base 16 connected to the mirror drive unit 13 through the rods 15, a mirror 17 held by the mirror base 16, holding plates 18 fixed to the housing 11 and clamping a stay 2 fixed to a vehicular body (not shown), and a cover 19 for the holding plate 18.
The wiper main body 20 is equipped with a wiper arm 21, a primary lever 22 connected to the free end of the wiper arm 21, secondary levers 23 connected to both ends of the primary lever 22 so that they are pivotable, a vertebra 24 held over the secondary levers 23, and a wiper blade 25 pivotably held on the vertebra 24.
The link mechanism section 30 is equipped with a first link member 31 mounted at one end thereof on the output shaft 14a of the wiper drive unit 14, a second link member 32 coupled at one end thereof to the other end of the first link member 31 through a shaft 32, a third link member 35 coupled at one end thereof to the other end of the second link member 33 through a shaft 34, and a wiper shaft 40 coupled to the other end of the third link member 35. The third link member 35 is provided with a cylinder member 35a rotatably inserted into a cylindrical portion 11a protruding from the housing 11.
The wiper shaft 40 is equipped with a pair of shaft members 41 and 42 and a coupling member 43. The coupling member 43 couples one end of the inner shaft member 41 and one end of the outer shaft member 42 together, thereby making the intermediate portion of the wiper shaft 40 bendable and allowing rotation of the wiper shaft 40.
The other end of the inner shaft member 41 (one end of the wiper shaft 40) is held in the cylinder member 35a so that it cannot rotate relative to the cylinder member 35a and can slide along the axial direction of the cylinder member 35a. Therefore, the rotary motion of the output shaft 14a is converted to reciprocal rotary motion by the link members 31, 33, and 35, and this reciprocal rotary motion is transferred to the wiper shaft 40.
The other end of the outer shaft member 42 (the other end of the wiper shaft 40) passes through holes formed in the mirror base 16 and mirror 17 and is fixed to the base portion 21a of the wiper arm 21 by means of a nut 26.
In the above-mentioned constitution, if the wiper drive unit 14 is driven, the output shaft 14a will rotate. This rotation causes the inner shaft member 41 to reciprocate and rotate within the cylindrical portion 11a integrally with the cylinder member 35a through the link mechanism section 30. At the same time, the outer shaft member 42 reciprocates and rotates integrally with the inner shaft member 41 through the coupling member 43, whereby the wiper arm 21 reciprocates and rotates. This reciprocation and rotation of the wiper arm 21 causes the wiper blade 25 to wipe the surface of the mirror 17.
The range of rotation of the wiper shaft 40 depends upon the setting of the link mechanism section 30. The coupled position of the wiper arm 21 relative to the wiper shaft 40 is adjusted according to the range of rotation of the wiper shaft 40. With this, the wiping range of the wiper blade 25 relative to the mirror 17 is determined.
Note that the wiping range is set so that it is slightly narrower than the reciprocal rotary motion range of the wiper main body 20 by protruding the housing 11 from the surface of the mirror 17. Therefore, if the wiper blade 25 abuts on the housing 11, the reciprocal rotary motion range will be consistent with the wiping range. At this time, even if the reciprocal rotary motion range of the wiper main body 20 is wider than the wiping range, the difference will be slight and therefore there will be no possibility that deformation of the wiper arm 21, damage to the wiper motor within the wiper drive unit 14, etc., will occur. In other words, the wiping range is set so that it is within an allowable range in which deformation of the wiper arm 21 and damage to the wiper motor will not occur.
Incidentally, in the wiper for a vehicular mirror constituted as described above, the mirror drive unit 13 and the wiper drive unit 14 are provided independently of each other. Moreover, the wiper drive unit 14 is provided at a position away from the mirror drive unit 13. For this reason, the output shaft 14a of the wiper drive unit 14 and the shaft 32 are at positions away from the wiper shaft 40.
Therefore, there is a need to assemble the mirror drive unit 13 and the wiper drive unit 14 separately in the housing 14. This assembly results in high rises in the part cost, such as screws, and the assembling operation cost. In addition, the third link member 35 extending between the output shaft 14a and the shaft 32 becomes long. To make the third link member 35 long, there is a disadvantage that the third link member 35 must be designed so as to bypass the mirror drive unit 13.